Number of Securities Transferred from Level Three to Level Two

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Other Than Temporary Impairment Non Credit Losses Portion Net Unrealized Losses Gains Related To Securities Net of Tax

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Percentage of fair value under carrying value.

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- Definition

Weighted Average Expected Maturity Of Securities

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of expenses related to the generation of investment income.

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Percent of net assets at close of period. For schedules of investments that are categorized, each category has a percent of net assets for the aggregated value of the Investments in the category.

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Incentive fees which are compensation paid to a trading advisor or to any practitioner who achieves investment results above a specified contractual level.

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Total assets that cannot be used for operating purposes because of contract or regulatory requirements that are in effect for a period that extends beyond one year.

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Investments - Additional Information (Detail) (USD $)	12 Months Ended
Investments - Additional Information (Detail) (USD $)	Dec. 31, 2014 Securities	Dec. 31, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Non-credit OTTI on fixed maturities in an unrealized gain position	$ 700,000	$ 500,000
Gross Unrealized Loss	1,304,000	550,000
Investment Expenses	2,998,000	3,256,000	10,386,000
Investment performance fee			2,800,000
Number of securities transferred from Level 3 to Level 2	1
Level 3 assets		4,407,000	0
Total Restricted Net Assets	523,425,000us-gaap_OtherRestrictedAssets	520,886,000us-gaap_OtherRestrictedAssets
Settlement Agreement
Schedule of Investments [Line Items]
Investment Expenses			4,500,000
Mortgage-backed and asset-backed securities
Schedule of Investments [Line Items]
Securities, effective maturities	4 years 4 months 24 days
Equity Securities \| Maximum
Schedule of Investments [Line Items]
Percentage of fair value under carrying value	80.00%
Non-government-backed securities
Schedule of Investments [Line Items]
Gross Unrealized Loss	$ 500,000	$ 1,100,000
Non-government-backed securities \| Maximum
Schedule of Investments [Line Items]
Percentage of investment	5.00%	5.00%